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Finding the Third Proportional to 21.12 and 30.85

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Solution

The third proportional to 21.12 and 30.85 is: 45.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.12 : 30.85 = 30.85 : x
  2. Step 2: Convert to fraction form
    21.12/30.85 = 30.85/x
  3. Step 3: Cross multiply
    21.12x = 30.85 × 30.85
  4. Step 4: Simplify right side
    21.12x = 951.70
  5. Step 5: Solve for x
    x = 951.70/21.12
  6. Step 6: Final answer
    x = 45.06

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.46) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.